A perpendicular spin orbit torque (SOT) memory device includes an electrode having a spin orbit coupling material and a magnetic tunnel junction (MTJ) device on a portion of the electrode. The electrode has a first SOC layer and a second SOC layer on a portion of the first SOC layer, where at least a portion of the first SOC layer at an interface with the second SOC layer includes oxygen.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A spin orbit torque (SOT) device, comprising: a fixed magnet; a first electrode coupled with the fixed magnet; a free magnet; a tunnel barrier between the free magnet and the fixed magnet; and a spin orbit torque (SOT) electrode coupled with the free magnet, the SOT electrode comprising: a first layer comprising a spin orbit coupling material, wherein the first layer has a first lateral length; and a second layer comprising the spin orbit coupling material, wherein: the second layer is between the free magnet and the first layer; the second layer is in contact with the first layer over a second lateral length that is smaller than the first lateral length; and at least a portion of the first layer at an interface with the second layer comprises oxygen.
2. The SOT device of claim 1 , wherein the portion of the first layer comprising oxygen is a first portion and has a thickness between 0.1 nm and 0.3 nm.
3. The SOT device of claim 1 , wherein a second portion of the first layer at an interface with the second layer comprises no oxygen.
4. The SOT device of claim 1 , wherein the portion of the first layer at an interface with the second layer comprises a greater concentration of oxygen compared to oxygen at an interface between the second layer and the free magnet.
5. The SOT device of claim 1 , wherein an uppermost surface of the first layer has a surface roughness that is less than a surface roughness of an uppermost surface of the second layer.
6. The SOT device of claim 1 , wherein the first layer is a first width and the second layer is the first width.
7. The SOT device of claim 6 , wherein the free magnet has a diameter equal to the first width and the second lateral length.
8. The SOT device of claim 1 , wherein an uppermost surface of the first layer not covered by the second layer is recessed below a lowermost surface of the second layer, wherein the amount of recess is less than a thickness of the remaining first layer.
9. The SOT device of claim 1 , wherein the SOT device further comprises a conductive layer adjacent to a sidewall of the first layer and between the sidewall of the first layer and a dielectric layer.
10. The SOT device of claim 9 , wherein the first layer extends over an uppermost surface of the conductive layer.
11. The SOT device of claim 10 , wherein at least a portion of the uppermost surface of the conductive layer proximal to the second layer comprises oxygen.
12. A method of fabricating a spin orbit torque (SOT) device, the method comprising: depositing and planarizing a first layer including a spin orbit coupling material; depositing a second layer including the spin orbit coupling material on the first layer, wherein at least a portion of the first layer at an interface with the second layer comprises oxygen; forming a material layer stack for a magnetic tunnel junction (MTJ) memory device, the forming comprising: depositing a fixed magnetic layer; depositing a tunnel barrier layer over the fixed magnetic layer; and depositing a free magnetic layer over the tunnel barrier layer; etching the material layer stack, wherein the etching forms a magnetic tunnel junction (MTJ) device; and etching the second layer including the spin orbit coupling material to have a second lateral length that is smaller than a first lateral length of the first layer by using the MTJ device as a mask.
13. The method of claim 12 , wherein the method further comprises: forming an opening in a dielectric layer; depositing a conductive layer in the opening prior to depositing the first layer including the spin orbit coupling material; depositing the first layer including the spin orbit coupling material on the conductive layer; and planarizing the spin orbit coupling material, portions of the conductive layer and the dielectric layer to form a first spin orbit torque (SOT) electrode in the opening.
14. The method of claim 12 , wherein etching the second layer comprises etching the portion of the first layer comprising oxygen.
15. The method of claim 14 , wherein the etching further comprises recessing an uppermost portion of the first layer by an amount less than a thickness of the second layer.
16. The method of claim 12 , further comprises forming a dielectric spacer layer adjacent to the MTJ device.
17. An apparatus comprising: a transistor above a substrate, the transistor comprising: a drain contact coupled to a drain; a source contact coupled to a source; a gate contact coupled to a gate; and a spin orbit torque (SOT) device coupled with the drain contact, the SOT device comprising: a fixed magnet; a first electrode coupled with the fixed magnet; a free magnet; a tunnel barrier between the free magnet and the fixed magnet; and a spin orbit torque (SOT) electrode coupled with the free magnet, the SOT electrode comprising: a first layer comprising a spin orbit coupling material, wherein the first layer has a first lateral length; and a second layer comprising the spin orbit coupling material, wherein: the second layer is between the free magnet and the first layer; the second layer is in contact with the first layer over a second lateral length that is smaller than the first lateral length; and at least a portion of the first layer at an interface with the second layer comprises oxygen; and a conductive interconnect coupled with the SOT electrode, wherein the MTJ device is between the conductive electrode and the drain contact.
18. The apparatus of claim 17 , wherein the portion of the first layer comprising oxygen is a first portion and has a thickness between 0.1 nm and 0.3 nm.
19. The apparatus of claim 17 , wherein a second portion of the first layer at an interface with the second layer comprises no oxygen.
20. The apparatus of claim 17 , wherein the first layer is a first width and the second layer is the first width, and wherein the free magnet has a diameter equal to the first width and the second lateral length.
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June 29, 2018
June 14, 2022
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